The ectoparasitic gamasid mites found on small mammals are important arthropods in the field of medical entomology. This paper studied the distribution and ecological niches of ectoparasitic gamasid mites on small mammal hosts in Yunnan Province of southwest China. Levins' niche breadth and Colwell-Futuyma's method were used to quantitatively evaluate host-specificity and similarity of host selection, and hierarchical analysis was used to illustrate niche overlap among gamasid mite species. Species diversity of both small mammals and gamasid mites was lower in indoor habitats than that in outdoor habitats. Most gamasid mite species were found on the body surface of the host species and niche breadths varied from species to species. A species with low niche breadth indicates high host specificity and most gamasid mites showed a relatively low niche overlap. The results suggest that a coevolutionary relationship may exist between some species of gamasid mites and their small mammal hosts.
Ectoparasitic gamasid mites (Acari: Mesostigmata) on the body surface of small mammals (especially rodents and insectivores) are generally regarded as an important group of medical arthropods because some are suspected as potential vectors of more than 20 zoonoses. Besides dermatitis caused by feeding ectoparasitic gamasid mites, it has been proved that some gamasid mites could be vectors of rickettsial pox and hemorrhagic fever with renal syndrome (HFRS) [
A map of Yunnan Province of China, showing the 28 investigated sites (28 counties).
The investigation compiled data came from 28 counties (28 investigation sites) in Yunnan Province (
Small mammals (rodents, shrews, moles, sciurids, and lagomorphs) were captured with mousetraps or mouse cages (
Representative voucher specimens of small mammal and gamasid mite were deposited in the specimen repository of Institute of Pathogens and Vectors, Dali University, China.
The constituent ratios (
Based on the constituent ratios of collected gamasid mites, 30 dominant mite species were chosen as the target mites for measurement of ecological niche and overlap. The total constituent ratio of the 30 dominant mite species (target mite species) reached 97.68% and the rest 82 rare mite species were not considered because they were so rare. The 67 species of small mammals were regarded as 67 series of potential host resources. The individual distribution proportion (ratio) of each mite species on all 67 series of host resources was then calculated and regarded as the utilization proportion on host resources. Based on the utilization proportions, Levins’ niche breadth was used to evaluate the host-specificity [
The following proportional similarity of niche by Colwell-Futuyma was used to measure niche overlap between two species of gamasid mites [
All analyses were carried out in SPSS 16.0 for Windows (SPSS Inc
A total of 14,544 individual small mammals were captured from 1990 to 2008 in the 28 counties (28 sampled sites) and identified as representing 10 families, 35 genera, and 67 species in five orders (Rodentia, Insectivora, Scandentia, Lagomorpha, and Carnivora). We collected 80,791 individual gamasid mites that were identified as 10 families, 33 genera, and 112 species.
Species diversities of small mammals were much lower indoors than outdoors; that is, much fewer species were found in indoors than in outdoors (
Dominant small mammal hosts captured and number of gamasid mite species collected in Yunnan Province of southwest China.
Names of dominant small mammal hosts | Number of hosts collected | Constituent ratios of the hosts (%) | Number of mite species | Number of mite individuals | Mite abundance | Habitat distribution of the hosts |
---|---|---|---|---|---|---|
3859 | 26.53 | 43 | 18459 | 4.78 | Indoor | |
1870 | 12.86 | 50 | 3018 | 1.61 | Outdoor | |
1802 | 12.39 | 41 | 2258 | 1.25 | Outdoor | |
1262 | 8.68 | 31 | 6102 | 4.84 | Indoor | |
697 | 4.79 | 34 | 13559 | 19.45 | Outdoor | |
580 | 3.99 | 32 | 11765 | 20.28 | Outdoor | |
540 | 3.71 | 26 | 562 | 1.04 | Outdoor | |
464 | 3.19 | 44 | 5394 | 11.63 | Outdoor | |
376 | 2.59 | 33 | 2258 | 6.01 | Outdoor | |
280 | 1.93 | 20 | 501 | 1.79 | Outdoor | |
278 | 1.91 | 18 | 204 | 0.73 | Outdoor | |
254 | 1.75 | 25 | 196 | 0.77 | Outdoor | |
253 | 1.74 | 37 | 842 | 3.33 | Outdoor | |
237 | 1.63 | 19 | 159 | 0.67 | Outdoor | |
235 | 1.62 | 22 | 139 | 0.59 | Outdoor | |
210 | 1.44 | 12 | 156 | 0.74 | Indoor | |
197 | 1.35 | 29 | 7058 | 35.83 | Outdoor | |
151 | 1.04 | 24 | 2445 | 16.19 | Outdoor | |
105 | 0.72 | 13 | 75 | 5.77 | Outdoor | |
96 | 0.66 | 16 | 880 | 55.00 | Outdoor | |
83 | 0.57 | 13 | 133 | 10.23 | Outdoor | |
72 | 0.50 | 11 | 140 | 12.73 | Outdoor | |
67 | 0.46 | 13 | 326 | 25.08 | Outdoor | |
64 | 0.44 | 5 | 28 | 5.60 | Outdoor | |
54 | 0.37 | 11 | 594 | 54.00 | Outdoor | |
45 | 0.31 | 18 | 603 | 33.50 | Outdoor | |
44 | 0.30 | 3 | 12 | 4.00 | Outdoor | |
38 | 0.26 | 12 | 245 | 20.42 | Outdoor | |
33 | 0.23 | 15 | 165 | 11.00 | Outdoor | |
28 | 0.19 | 4 | 4 | 1.00 | Outdoor | |
26 | 0.18 | 4 | 126 | 31.50 | Outdoor | |
23 | 0.16 | 4 | 16 | 4.00 | Outdoor | |
18 | 0.12 | 3 | 39 | 13.00 | Outdoor | |
14 | 0.10 | 5 | 6 | 1.20 | Outdoor |
Annotation: The remaining small mammal hosts whose constituent ratios were lower than 0.1% and are not included in Table
The number of mite species on mammals varies from host species to species (from 3 to 50 species,
Although some small mammals harbored large numbers of mite species, most individuals had one or more mite species as the dominant ectoparasitics. For example,
In this paper, only 30 dominant species of gamasid mites were chosen as target species and they accounted for 97.68% of the total mite species collected. The distribution and host selection of gamasid mites varied from species to species. Some gamasid mite species often parasitized one or two species of mammal hosts and examples include the following mite species:
Host ranges and niche breadth of 30 dominant gamasid mites species on 67 species of small mammal hosts.
Dominant gamasid mite species | Codes of the mites species | Number of mite individuals | Constituent ratios of the mites (%) | Number of infested host species (host ranges) | Niche breadths |
---|---|---|---|---|---|
1 | 20248 | 25.06 | 28 | 0.0397 | |
2 | 15840 | 19.61 | 23 | 0.0622 | |
3 | 10444 | 12.93 | 17 | 0.0156 | |
4 | 6429 | 7.96 | 31 | 0.0402 | |
5 | 4165 | 5.16 | 25 | 0.0448 | |
6 | 3340 | 4.13 | 15 | 0.0360 | |
7 | 2734 | 3.38 | 28 | 0.0450 | |
8 | 2358 | 2.92 | 15 | 0.0165 | |
9 | 1979 | 2.45 | 9 | 0.0154 | |
10 | 1933 | 2.39 | 6 | 0.0158 | |
11 | 1099 | 1.36 | 27 | 0.0880 | |
12 | 955 | 1.18 | 8 | 0.0163 | |
13 | 923 | 1.14 | 10 | 0.0343 | |
14 | 832 | 1.03 | 13 | 0.0163 | |
15 | 815 | 1.01 | 9 | 0.0175 | |
16 | 689 | 0.85 | 24 | 0.0842 | |
17 | 651 | 0.81 | 23 | 0.1475 | |
18 | 422 | 0.52 | 11 | 0.0186 | |
19 | 410 | 0.51 | 12 | 0.0381 | |
20 | 391 | 0.48 | 27 | 0.1646 | |
21 | 374 | 0.46 | 2 | 0.0156 | |
22 | 369 | 0.46 | 19 | 0.0606 | |
23 | 290 | 0.36 | 14 | 0.1027 | |
24 | 273 | 0.34 | 11 | 0.0230 | |
25 | 244 | 0.30 | 7 | 0.0191 | |
26 | 154 | 0.19 | 11 | 0.0731 | |
27 | 149 | 0.18 | 8 | 0.0429 | |
28 | 138 | 0.17 | 17 | 0.0765 | |
29 | 134 | 0.17 | 16 | 0.0420 | |
30 | 131 | 0.16 | 19 | 0.1566 |
The mite infestation rates of small mammals with 30 dominant gamasid mite species.
Dominant host species | Infestation rate of 30 dominant mite species (%) | |||||||||||||||||||||||||||||
1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | |
22.49 | 26.79 | 0.08 | 0.10 | 0.10 | 7.62 | 0.05 | 0.00 | 0.00 | 0.05 | 1.68 | 0.03 | 0.00 | 0.00 | 0.00 | 1.55 | 0.00 | 0.00 | 0.00 | 0.31 | 0.00 | 0.00 | 0.13 | 2.23 | 1.22 | 0.00 | 0.03 | 0.75 | 0.88 | 0.16 | |
1.66 | 1.39 | 0.43 | 0.96 | 0.96 | 0.16 | 1.18 | 0.32 | 0.21 | 0.00 | 6.04 | 0.05 | 0.00 | 0.00 | 4.33 | 1.98 | 3.37 | 5.99 | 2.57 | 2.19 | 0.00 | 2.94 | 0.64 | 0.16 | 0.00 | 0.70 | 0.00 | 0.43 | 0.37 | 0.43 | |
0.39 | 0.44 | 0.55 | 0.61 | 1.28 | 0.06 | 28.25 | 0.00 | 0.39 | 0.00 | 0.89 | 0.00 | 0.06 | 0.06 | 0.44 | 1.55 | 5.38 | 0.22 | 0.50 | 2.55 | 0.00 | 0.78 | 1.17 | 0.00 | 0.00 | 1.78 | 0.33 | 0.39 | 0.06 | 0.28 | |
16.64 | 20.44 | 0.16 | 0.32 | 0.32 | 10.70 | 0.48 | 0.00 | 0.08 | 0.32 | 3.25 | 0.16 | 0.00 | 0.00 | 0.08 | 2.14 | 0.24 | 0.08 | 0.16 | 0.55 | 0.00 | 0.16 | 0.24 | 0.63 | 0.24 | 0.08 | 0.00 | 0.08 | 0.16 | 0.40 | |
0.00 | 1.00 | 80.92 | 1.58 | 0.00 | 0.00 | 0.72 | 0.14 | 49.64 | 0.72 | 2.44 | 43.47 | 0.14 | 0.14 | 0.00 | 1.87 | 1.00 | 0.14 | 0.00 | 1.72 | 0.00 | 0.29 | 0.00 | 0.00 | 0.00 | 0.00 | 1.15 | 2.15 | 0.57 | 1.15 | |
47.07 | 67.76 | 0.17 | 1.03 | 0.34 | 0.52 | 0.69 | 0.00 | 0.17 | 0.00 | 8.97 | 0.00 | 0.17 | 0.00 | 0.00 | 8.28 | 0.34 | 0.00 | 0.00 | 2.24 | 0.00 | 0.17 | 0.34 | 1.38 | 0.52 | 0.00 | 0.00 | 0.34 | 0.34 | 1.21 | |
0.19 | 0.19 | 0.00 | 2.41 | 5.00 | 0.56 | 5.37 | 0.00 | 0.00 | 0.00 | 0.37 | 0.00 | 0.00 | 0.00 | 0.19 | 0.56 | 8.33 | 0.00 | 22.04 | 1.48 | 0.00 | 3.33 | 0.00 | 0.00 | 0.00 | 5.74 | 0.00 | 0.00 | 0.00 | 0.19 | |
1.29 | 26.08 | 0.65 | 50.43 | 40.95 | 0.22 | 1.94 | 0.22 | 0.00 | 0.00 | 1.51 | 0.22 | 4.09 | 0.43 | 0.22 | 2.37 | 3.88 | 0.00 | 1.72 | 5.17 | 0.65 | 0.65 | 0.22 | 0.43 | 0.00 | 1.29 | 0.00 | 0.43 | 0.65 | 1.29 | |
4.79 | 0.80 | 2.13 | 1.33 | 0.00 | 0.27 | 0.80 | 0.00 | 0.53 | 52.13 | 0.53 | 2.13 | 0.00 | 0.00 | 0.00 | 3.19 | 0.00 | 0.53 | 0.00 | 1.06 | 0.00 | 5.32 | 0.27 | 1.06 | 0.00 | 0.00 | 0.00 | 4.26 | 0.53 | 0.80 | |
10.36 | 2.14 | 1.43 | 2.14 | 0.71 | 0.00 | 1.43 | 0.71 | 0.00 | 0.00 | 2.14 | 0.00 | 0.00 | 0.00 | 0.00 | 1.07 | 6.43 | 4.29 | 6.07 | 2.86 | 0.00 | 5.36 | 0.71 | 0.00 | 0.00 | 3.57 | 0.36 | 0.00 | 0.00 | 0.36 | |
3.96 | 0.36 | 0.00 | 0.00 | 0.36 | 0.00 | 1.08 | 0.00 | 0.36 | 0.00 | 3.60 | 0.00 | 0.00 | 0.36 | 1.44 | 0.00 | 5.76 | 1.08 | 10.43 | 1.08 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | |
9.06 | 1.97 | 0.39 | 0.39 | 0.00 | 2.36 | 0.79 | 1.18 | 0.00 | 0.00 | 1.57 | 0.00 | 0.00 | 0.00 | 0.00 | 3.54 | 0.39 | 0.00 | 0.00 | 2.36 | 0.00 | 0.00 | 0.00 | 1.57 | 0.00 | 0.00 | 0.00 | 2.36 | 2.36 | 2.36 | |
20.16 | 15.02 | 1.19 | 6.32 | 1.98 | 2.77 | 0.40 | 0.40 | 0.00 | 0.00 | 8.30 | 0.00 | 0.00 | 0.00 | 0.79 | 3.16 | 1.98 | 0.00 | 0.00 | 3.16 | 0.00 | 1.19 | 0.79 | 0.40 | 0.79 | 0.00 | 0.00 | 2.37 | 1.58 | 3.56 | |
0.84 | 1.69 | 0.42 | 0.84 | 1.69 | 0.84 | 0.42 | 0.42 | 0.00 | 0.00 | 2.11 | 0.00 | 0.00 | 0.42 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.84 | 0.00 | 0.00 | 0.00 | 0.00 | 0.42 | 0.00 | 0.00 | 0.00 | 0.42 | 0.42 | |
3.83 | 2.13 | 0.43 | 0.43 | 0.00 | 2.98 | 0.43 | 0.85 | 0.00 | 0.00 | 3.40 | 0.00 | 0.00 | 0.00 | 0.00 | 0.85 | 0.00 | 0.43 | 0.00 | 0.85 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.43 | 0.43 | 0.43 | |
1.43 | 2.86 | 0.95 | 0.48 | 0.00 | 4.76 | 0.00 | 0.00 | 0.48 | 0.95 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.95 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.48 | 0.00 | 0.48 | 0.00 | 0.00 | 0.00 | 0.48 | 0.00 | |
5.08 | 56.35 | 0.00 | 67.01 | 40.61 | 0.00 | 0.00 | 0.00 | 0.51 | 0.00 | 4.57 | 0.51 | 5.08 | 0.00 | 0.00 | 2.54 | 1.02 | 0.00 | 0.00 | 1.52 | 0.00 | 1.02 | 0.51 | 0.00 | 0.00 | 0.00 | 0.51 | 0.51 | 0.51 | 0.00 | |
1.32 | 3.31 | 0.00 | 0.66 | 0.00 | 0.00 | 0.66 | 35.76 | 0.00 | 0.00 | 3.97 | 0.00 | 0.00 | 0.00 | 0.00 | 0.66 | 3.31 | 0.00 | 0.00 | 4.64 | 0.00 | 0.00 | 1.32 | 0.00 | 0.00 | 0.00 | 0.00 | 0.66 | 0.00 | 2.65 | |
0.95 | 0.00 | 0.00 | 2.86 | 0.00 | 0.95 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.95 | 0.95 | 4.76 | 12.38 | 0.00 | 10.48 | 0.95 | 0.00 | 2.86 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | |
0.00 | 0.00 | 0.00 | 4.17 | 5.21 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 53.13 | 0.00 | 0.00 | 1.04 | 0.00 | 2.08 | 1.04 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 3.13 | 0.00 | 1.04 | 1.04 | |
4.82 | 7.23 | 3.61 | 2.41 | 0.00 | 0.00 | 2.41 | 0.00 | 0.00 | 1.20 | 1.20 | 10.84 | 0.00 | 0.00 | 2.41 | 1.20 | 1.20 | 2.41 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 4.82 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | |
1.39 | 0.00 | 0.00 | 0.00 | 12.50 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 5.56 | 0.00 | 0.00 | 2.78 | 0.00 | 0.00 | 1.39 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 1.39 | 0.00 | 0.00 | 0.00 | |
1.49 | 0.00 | 0.00 | 0.00 | 1.49 | 0.00 | 43.28 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 4.48 | 1.49 | 2.99 | 1.49 | 2.99 | 0.00 | 4.48 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 1.49 | 1.49 | 0.00 | |
0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 1.56 | 0.00 | 0.00 | 0.00 | 1.56 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 3.13 | 0.00 | 0.00 | 0.00 | 1.56 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | |
3.70 | 16.67 | 0.00 | 44.44 | 51.85 | 1.85 | 3.70 | 0.00 | 0.00 | 0.00 | 1.85 | 0.00 | 12.96 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 5.56 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 1.85 | 0.00 | 0.00 | |
0.00 | 2.22 | 4.44 | 8.89 | 4.44 | 0.00 | 0.00 | 8.89 | 0.00 | 0.00 | 6.67 | 0.00 | 0.00 | 0.00 | 0.00 | 6.67 | 0.00 | 0.00 | 0.00 | 6.67 | 66.67 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 2.22 | 0.00 | 4.44 | |
0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 4.55 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 4.55 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | |
2.63 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 52.63 | 2.63 | 0.00 | 0.00 | 2.63 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 15.79 | 0.00 | 0.00 | 0.00 | 0.00 | 2.63 | 0.00 | 0.00 | 0.00 | 0.00 | 13.16 | 0.00 | 0.00 | 0.00 | |
6.06 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 3.03 | 9.09 | 0.00 | 0.00 | 3.03 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 3.03 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | |
0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 3.57 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 3.57 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | |
0.00 | 0.00 | 0.00 | 15.38 | 3.85 | 0.00 | 3.85 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 34.62 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | |
0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 4.35 | 8.70 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 4.35 | |
0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 22.22 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | |
0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 7.14 | 0.00 | 0.00 | 0.00 | 0.00 | 7.14 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 |
Annotation: The rest small mammal hosts whose constituent ratios lower than 0.1% were not included in Table
In our study, we found that some species achieve maximum individual abundant on certain host species, that is
The distribution of 30 dominant species of gamasid mites on dominant small mammal hosts.
Dominant host species | ||||||||||||||||||||||||||||||
Constituent ratios of 30 dominant mite species (%) | ||||||||||||||||||||||||||||||
1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | |
52.83 | 32.75 | 0.04 | 1.07 | 2.06 | 41.74 | 0.11 | 0.00 | 0.00 | 0.10 | 11.92 | 0.10 | 0.00 | 0.00 | 0.00 | 23.95 | 0.00 | 0.00 | 0.00 | 3.58 | 0.00 | 0.00 | 3.79 | 79.85 | 88.11 | 0.00 | 0.67 | 33.33 | 57.46 | 6.87 | |
0.75 | 1.98 | 0.47 | 2.29 | 1.34 | 0.15 | 2.21 | 0.38 | 0.30 | 0.00 | 33.58 | 0.10 | 0.00 | 0.00 | 5.81 | 20.89 | 89.34 | 26.59 | 17.65 | 0.00 | 35.50 | 21.03 | 1.10 | 0.00 | 11.04 | 0.00 | 9.42 | 8.96 | 10.69 | ||
0.03 | 0.39 | 0.05 | 0.23 | 0.89 | 0.03 | 55.72 | 0.00 | 0.15 | 0.00 | 2.09 | 0.00 | 0.33 | 0.48 | 2.45 | 2.03 | 20.28 | 1.18 | 3.90 | 16.88 | 0.00 | 0.54 | 12.07 | 0.00 | 0.00 | 24.68 | 55.70 | 4.35 | 0.75 | 5.34 | |
12.08 | 10.32 | 0.05 | 0.20 | 0.12 | 48.71 | 0.72 | 0.00 | 0.10 | 0.47 | 11.46 | 0.42 | 0.00 | 0.00 | 0.25 | 12.48 | 2.00 | 0.24 | 0.49 | 2.81 | 0.00 | 0.54 | 1.03 | 3.66 | 1.23 | 0.65 | 0.00 | 0.72 | 5.97 | 9.16 | |
0.00 | 0.14 | 0.59 | 0.00 | 0.00 | 1.30 | 0.08 | 1.09 | 5.64 | 0.22 | 2.04 | 0.00 | 2.61 | 1.84 | 0.00 | 0.00 | 3.58 | 0.00 | 0.81 | 0.00 | 0.00 | 0.00 | 0.00 | 17.45 | 15.94 | 2.99 | 14.50 | ||||
28.62 | 32.94 | 0.12 | 0.11 | 0.19 | 4.07 | 0.29 | 0.00 | 0.25 | 0.00 | 12.74 | 0.00 | 3.79 | 0.00 | 0.00 | 31.06 | 0.46 | 0.24 | 0.00 | 6.65 | 0.00 | 0.27 | 28.97 | 6.59 | 1.64 | 0.00 | 0.00 | 1.45 | 2.99 | 9.16 | |
0.04 | 0.01 | 0.00 | 0.44 | 0.96 | 0.30 | 1.30 | 0.00 | 0.00 | 0.00 | 0.18 | 0.00 | 0.00 | 0.00 | 0.37 | 0.87 | 8.76 | 0.00 | 53.66 | 3.07 | 0.00 | 10.84 | 0.00 | 0.00 | 0.00 | 32.47 | 0.00 | 0.00 | 0.00 | 0.76 | |
0.17 | 7.46 | 0.11 | 37.74 | 32.03 | 0.09 | 0.43 | 0.04 | 0.00 | 0.00 | 1.18 | 0.10 | 23.62 | 0.24 | 0.12 | 2.32 | 3.07 | 0.00 | 2.20 | 6.91 | 2.14 | 0.54 | 0.34 | 0.73 | 0.00 | 5.19 | 0.00 | 2.17 | 3.73 | 6.11 | |
0.89 | 0.04 | 0.26 | 0.50 | 0.00 | 0.03 | 0.07 | 0.00 | 0.35 | 0.36 | 2.20 | 0.00 | 0.00 | 0.00 | 2.61 | 0.00 | 1.18 | 0.00 | 1.02 | 0.00 | 0.00 | 0.69 | 1.83 | 0.00 | 0.00 | 0.00 | 20.29 | 1.49 | 3.05 | ||
0.60 | 0.28 | 0.48 | 0.48 | 0.05 | 0.00 | 0.00 | 0.21 | 0.00 | 0.00 | 0.55 | 0.00 | 0.00 | 0.00 | 0.00 | 0.44 | 4.61 | 5.45 | 9.76 | 3.07 | 0.00 | 31.71 | 0.69 | 0.00 | 0.00 | 0.00 | 0.67 | 0.00 | 0.00 | 0.76 | |
0.14 | 0.01 | 0.00 | 0.00 | 0.05 | 0.00 | 0.18 | 0.00 | 0.05 | 0.00 | 1.82 | 0.00 | 0.00 | 0.12 | 1.23 | 0.00 | 5.22 | 0.95 | 13.90 | 1.02 | 0.00 | 8.13 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | |
0.23 | 0.06 | 0.01 | 0.03 | 0.00 | 0.39 | 0.11 | 0.38 | 0.00 | 0.00 | 0.91 | 0.00 | 0.00 | 0.00 | 0.00 | 2.03 | 0.15 | 0.00 | 0.00 | 2.81 | 0.00 | 0.00 | 0.00 | 5.13 | 0.00 | 0.00 | 0.00 | 4.35 | 8.21 | 6.11 | |
1.19 | 1.17 | 0.04 | 2.58 | 0.19 | 0.42 | 0.04 | 0.04 | 0.00 | 0.00 | 8.55 | 0.00 | 0.00 | 0.00 | 0.25 | 1.89 | 1.23 | 0.00 | 0.00 | 5.37 | 0.00 | 1.08 | 0.69 | 0.37 | 2.05 | 0.00 | 0.00 | 5.80 | 4.48 | 16.79 | |
0.01 | 0.03 | 0.01 | 0.08 | 0.58 | 0.24 | 0.04 | 0.00 | 0.00 | 0.00 | 1.00 | 0.00 | 0.00 | 0.60 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.77 | 0.00 | 0.00 | 0.00 | 0.00 | 6.15 | 0.00 | 0.00 | 0.00 | 0.75 | 0.76 | |
0.14 | 0.10 | 0.02 | 0.08 | 0.00 | 0.30 | 0.11 | 0.17 | 0.00 | 0.00 | 1.09 | 0.00 | 0.00 | 0.00 | 0.00 | 3.05 | 0.00 | 0.71 | 0.00 | 0.51 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.72 | 0.75 | 1.53 | |
0.05 | 0.06 | 0.02 | 0.02 | 0.00 | 3.08 | 0.00 | 0.00 | 0.05 | 1.19 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.29 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.34 | 0.00 | 0.41 | 0.00 | 0.00 | 0.00 | 0.75 | 0.00 | |
0.08 | 8.64 | 0.00 | 47.51 | 47.32 | 0.00 | 0.00 | 0.00 | 0.05 | 0.00 | 0.36 | 0.10 | 60.78 | 0.00 | 0.00 | 1.31 | 0.92 | 0.00 | 0.00 | 0.77 | 0.00 | 3.25 | 1.03 | 0.00 | 0.00 | 0.00 | 0.67 | 0.72 | 3.73 | 0.00 | |
0.16 | 0.32 | 0.00 | 0.02 | 0.00 | 0.00 | 0.51 | 95.12 | 0.00 | 0.00 | 3.91 | 0.00 | 0.00 | 0.00 | 0.00 | 0.29 | 0.92 | 0.00 | 0.00 | 2.05 | 0.00 | 0.00 | 1.38 | 0.00 | 0.00 | 0.00 | 0.00 | 0.72 | 0.00 | 3.05 | |
0.00 | 0.00 | 0.00 | 0.05 | 0.00 | 0.03 | 0.18 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.12 | 0.12 | 0.87 | 2.15 | 0.00 | 4.15 | 0.26 | 0.00 | 0.81 | 0.00 | 0.00 | 0.00 | 11.69 | 0.00 | 0.00 | 0.00 | 0.00 | |
0.00 | 0.00 | 0.00 | 0.20 | 0.19 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.15 | 0.00 | 0.49 | 2.05 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 2.68 | 0.00 | 0.75 | 1.53 | ||
0.24 | 0.13 | 0.06 | 0.00 | 0.00 | 0.00 | 0.07 | 0.00 | 0.00 | 0.05 | 0.09 | 1.36 | 0.00 | 0.00 | 2.94 | 0.15 | 0.15 | 0.47 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 4.40 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | |
0.01 | 0.00 | 0.00 | 0.03 | 1.22 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.84 | 0.00 | 0.00 | 0.31 | 0.00 | 0.00 | 0.26 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.67 | 0.00 | 0.00 | 0.00 | |
0.00 | 0.00 | 0.00 | 0.00 | 0.05 | 0.00 | 9.01 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.29 | 0.15 | 0.24 | 0.24 | 0.51 | 0.00 | 0.54 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.72 | 0.75 | 0.00 | |
0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.80 | 0.00 | 0.00 | 0.00 | 0.27 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.26 | 0.00 | 0.00 | 0.00 | 0.37 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | |
0.03 | 0.14 | 0.00 | 3.92 | 6.87 | 0.00 | 0.36 | 0.04 | 0.00 | 0.00 | 0.09 | 0.00 | 0.65 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 1.02 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.72 | 0.00 | 0.00 | |
0.00 | 0.17 | 0.02 | 0.22 | 0.05 | 0.00 | 0.00 | 0.68 | 0.00 | 0.00 | 0.64 | 0.00 | 0.00 | 0.00 | 0.00 | 0.58 | 0.00 | 0.00 | 0.00 | 10.74 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.72 | 0.00 | 1.53 | ||
0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.18 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 2.07 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | |
0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 6.44 | 0.55 | 0.00 | 0.00 | 0.09 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 3.38 | 0.00 | 0.00 | 0.00 | 0.00 | 0.54 | 0.00 | 0.00 | 0.00 | 0.00 | 8.05 | 0.00 | 0.00 | 0.00 | |
0.01 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.36 | 0.51 | 0.00 | 0.00 | 0.18 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.27 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | |
0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.04 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.26 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | |
0.00 | 0.00 | 0.00 | 0.61 | 0.02 | 0.00 | 0.04 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 9.21 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | |
0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.11 | 0.24 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.76 | |
0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.60 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | |
0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.15 | 0.00 | 0.00 | 0.00 | 0.00 | 0.27 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 |
Annotation: The species codes of 30 dominant gamasid mite species are the same as those in Table
In the measurement of ecological niche, the individual distribution proportion (ratio) of each mite species on 67 series of host resources was used to calculate the breadth of gamasid mites. Most gamasid mite species could be found on the body surface of several host species (more than two host species at least) and niche breadths ranged from 0.0154 to 0.1646. Of the 30 mite species studied,
Three species of gamasid mites (
Niche overlaps among 30 species of gamasid mites.
Code | Gamasid | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 |
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
1 | 1 | ||||||||||||||||||||||||||||||
2 | 0.77 | 1 | |||||||||||||||||||||||||||||
3 | 0.03 | 0.03 | 1 | ||||||||||||||||||||||||||||
4 | 0.06 | 0.23 | 0.03 | 1 | |||||||||||||||||||||||||||
5 | 0.06 | 0.23 | 0.02 | 0.89 | 1 | ||||||||||||||||||||||||||
6 | 0.60 | 0.50 | 0.01 | 0.03 | 0.05 | 1 | |||||||||||||||||||||||||
7 | 0.11 | 0.14 | 0.10 | 0.13 | 0.14 | 0.10 | 1 | ||||||||||||||||||||||||
8 | 0.02 | 0.03 | 0.02 | 0.02 | 0.02 | 0.01 | 0.11 | 1 | |||||||||||||||||||||||
9 | 0.02 | 0.03 | 0.02 | 0.02 | 0.01 | 0.10 | 0.01 | 1 | |||||||||||||||||||||||
10 | 0.02 | 0.02 | 0.02 | 0.02 | 0.01 | 0.02 | 0.10 | 0.01 | 0.02 | 1 | |||||||||||||||||||||
11 | 0.41 | 0.43 | 0.08 | 0.11 | 0.09 | 0.30 | 0.17 | 0.07 | 0.07 | 0.02 | 1 | ||||||||||||||||||||
12 | 0.03 | 0.02 | 0.02 | 0.02 | 0.01 | 0.10 | 0.01 | 0.04 | 0.07 | 1 | |||||||||||||||||||||
13 | 0.05 | 0.22 | 0.01 | 0.73 | 0.73 | 0.04 | 0.10 | 0.01 | 0.01 | 0.00 | 0.06 | 0.00 | 1 | ||||||||||||||||||
14 | 0.01 | 0.02 | 0.00 | 0.01 | 0.04 | 0.01 | 0.09 | 0.01 | 0.00 | 0.00 | 0.02 | 0.00 | 0.01 | 1 | |||||||||||||||||
15 | 0.03 | 0.04 | 0.01 | 0.04 | 0.04 | 0.01 | 0.14 | 0.01 | 0.01 | 0.00 | 0.38 | 0.02 | 0.01 | 0.01 | 1 | ||||||||||||||||
16 | 0.72 | 0.77 | 0.07 | 0.14 | 0.13 | 0.45 | 0.20 | 0.05 | 0.07 | 0.07 | 0.56 | 0.08 | 0.11 | 0.03 | 0.12 | 1 | |||||||||||||||
17 | 0.19 | 0.25 | 0.16 | 0.23 | 0.23 | 0.16 | 0.48 | 0.15 | 0.15 | 0.14 | 0.47 | 0.15 | 0.18 | 0.14 | 0.38 | 0.35 | 1 | ||||||||||||||
18 | 0.04 | 0.05 | 0.02 | 0.04 | 0.04 | 0.01 | 0.12 | 0.01 | 0.01 | 0.01 | 0.38 | 0.02 | 0.01 | 0.01 | 0.92 | 0.13 | 0.41 | 1 | |||||||||||||
19 | 0.04 | 0.01 | 0.06 | 0.01 | 0.01 | 0.06 | 0.06 | 0.06 | 0.07 | 0.07 | 0.24 | 0.07 | 0.05 | 0.06 | 0.21 | 0.06 | 0.50 | 0.26 | 1 | ||||||||||||
20 | 0.26 | 0.35 | 0.13 | 0.26 | 0.26 | 0.20 | 0.42 | 0.12 | 0.13 | 0.11 | 0.58 | 0.13 | 0.21 | 0.12 | 0.30 | 0.45 | 0.74 | 0.33 | 0.29 | 1 | |||||||||||
21 | 0.01 | 0.04 | 0.00 | 0.02 | 0.03 | 0.00 | 0.08 | 0.01 | 0.00 | 0.00 | 0.02 | 0.00 | 0.02 | 0.00 | 0.00 | 0.05 | 0.15 | 0.00 | 0.05 | 0.10 | 1 | ||||||||||
22 | 0.06 | 0.12 | 0.04 | 0.11 | 0.10 | 0.04 | 0.18 | 0.04 | 0.04 | 0.03 | 0.43 | 0.03 | 0.06 | 0.03 | 0.40 | 0.18 | 0.60 | 0.45 | 0.52 | 0.40 | 0.02 | 1 | |||||||||
23 | 0.51 | 0.54 | 0.15 | 0.20 | 0.21 | 0.23 | 0.38 | 0.16 | 0.15 | 0.15 | 0.58 | 0.15 | 0.19 | 0.14 | 0.37 | 0.61 | 0.64 | 0.37 | 0.29 | 0.67 | 0.14 | 0.40 | 1 | ||||||||
24 | 0.64 | 0.44 | 0.01 | 0.02 | 0.03 | 0.48 | 0.08 | 0.01 | 0.01 | 0.00 | 0.24 | 0.01 | 0.02 | 0.02 | 0.02 | 0.41 | 0.15 | 0.01 | 0.07 | 0.25 | 0.02 | 0.02 | 0.25 | 1 | |||||||
25 | 0.58 | 0.38 | 0.00 | 0.04 | 0.04 | 0.46 | 0.09 | 0.01 | 0.01 | 0.01 | 0.18 | 0.00 | 0.02 | 0.01 | 0.00 | 0.32 | 0.15 | 0.00 | 0.07 | 0.17 | 0.00 | 0.04 | 0.21 | 0.81 | 1 | ||||||
26 | 0.02 | 0.10 | 0.01 | 0.09 | 0.10 | 0.01 | 0.37 | 0.01 | 0.01 | 0.00 | 0.15 | 0.01 | 0.06 | 0.01 | 0.14 | 0.15 | 0.58 | 0.12 | 0.44 | 0.45 | 0.02 | 0.26 | 0.37 | 0.00 | 0.01 | 1 | |||||
27 | 0.09 | 0.10 | 0.25 | 0.10 | 0.11 | 0.07 | 0.78 | 0.08 | 0.24 | 0.08 | 0.16 | 0.24 | 0.08 | 0.11 | 0.09 | 0.16 | 0.43 | 0.08 | 0.01 | 0.39 | 0.07 | 0.12 | 0.34 | 0.05 | 0.07 | 0.31 | 1 | ||||
28 | 0.38 | 0.42 | 0.15 | 0.11 | 0.09 | 0.35 | 0.17 | 0.01 | 0.15 | 0.20 | 0.40 | 0.17 | 0.04 | 0.01 | 0.11 | 0.48 | 0.34 | 0.11 | 0.03 | 0.45 | 0.01 | 0.14 | 0.34 | 0.40 | 0.36 | 0.15 | 0.27 | 1 | |||
29 | 0.65 | 0.53 | 0.03 | 0.14 | 0.12 | 0.52 | 0.12 | 0.00 | 0.03 | 0.02 | 0.40 | 0.04 | 0.09 | 0.00 | 0.08 | 0.52 | 0.30 | 0.10 | 0.03 | 0.43 | 0.01 | 0.16 | 0.32 | 0.69 | 0.62 | 0.12 | 0.10 | 0.58 | 1 | ||
30 | 0.31 | 0.39 | 0.18 | 0.17 | 0.16 | 0.24 | 0.22 | 0.07 | 0.18 | 0.07 | 0.62 | 0.19 | 0.12 | 0.05 | 0.16 | 0.52 | 0.41 | 0.16 | 0.09 | 0.63 | 0.04 | 0.19 | 0.48 | 0.26 | 0.14 | 0.25 | 0.31 | 0.54 | 0.46 | 1 |
Niche overlapping groups of gamasid mites.
Niche overlapping groups | Species of gamasid mites (Code) | Corresponding main hosts |
---|---|---|
Group 1 | ||
Group 2 | ||
Group 3 | ||
Group 4 | ||
Group 5 | ||
Group 6 | ||
Group 7 | ||
Group 8 | ||
Group 9 | ||
Group 10 | ||
Group 11 | ||
Group 12 | ||
Group 13 | ||
Group 14 | Genus | |
Group 15 |
The hierarchical cluster dendrogram of 30 mite species based on the Euclidean distance.
Mite assemblages on small mammalian hosts are strongly influenced by the ecological habitat of their hosts [
Small mammals are the food resource of ectoparasitic gamasid mites that consume the blood or body fluids from their hosts. The host range and Levins’ niche breadth should provide values opposite host specificity for ectoparasitic gamasid mites that use the hosts as their principle food resource [
Host specificity is the result of co-evolution between the parasite and their host and a high specificity often indicates a high degree of co-evolution. Therefore the niche breadth can also be used to demonstrate co-evolution between ectoparasites and their hosts [
Niche overlap estimates can approximate the degree that certain species partition resources within a certain community. Niche overlap measures the degree to which two different species share a particular resource and it reflects, in the case of gamasid mites, on small mammal hosts similarities of host resource utilization between two mites species in a certain community. When the host species are regarded as the food resource, a high niche overlap between any two mite species means that these species tend to choose the same or similar small mammal species, especially their dominant hosts. In contrast, a low niche overlap between any two mite species usually indicates a low similarity in host selection. The results showed that
Special thanks to Dr. Brian Forschler for editing language. We are grateful to the following people for their help during the previous field investigation and laboratory work: Dong Wen-ge, Qian Ti-jun, Wang Qiao-hua, Li Wei, Men Xing-yuan, Zhang Sheng-yong, Meng Yan-fen, Ren Tian-guang, Jing Yong-guang, and some college students in Dali University. The authors thank Dong Wen-ge, Yan Yi, and Wang Qiao-Hua for their help in the mite identification. We also thank the CDCs (Center of Disease Prevention and Control) in the 28 investigated counties for their kind support, help, and contributions. The project was funded by the Natural Science Foundation of China (Grant no. 30760226).